Abstract
Background: Favipiravir, first used for novel influenza
strains, is being used today in coronavirus disease 2019 (COVID-19).
While many studies have been reported in the literature on
hydroxychloroquine’s (HQ) arrhythmogenic adverse effects, data on
favipiravir are limited. The authors purposed to demonstrate that the
arrhythmic effects of favipiravir are not negligible.
Methods: The researchers conducted a retrospective
observational study on 194 COVID-19 patients. The study population was
classified into two groups based on the treatment regimen: favipiravir
(n=101) and HQ (n=93). Pre/post-medication electrocardiograms were
evaluated for arrhythmic events.
Results: Twenty of 101 (19.8%) subjects in the favipiravir
group and 13 of 93 (13.9%) subjects in the HQ group had arrhythmogenic
events (p=0.42). The most frequent arrhythmic events in the favipiravir
group were sinus bradycardia (13 of 20, 65%) and third-degree
atrioventricular block (4 of 20, 20%). Corrected QT (QTc) prolongation
was the most seen arrhythmogenic adverse effect (9 of 13, 69%) in the
HQ group. The proportion of patients with prolonged QTc were higher in
the HQ group than the favipiravir group (9 vs. 3, p=0.04). However, the
difference between final and baseline QTc did not differ between the HQ
and the favipiravir group (11 [IQR:-9—57] vs. 12
[IQR:-7—103], p=0.59, respectively). The change between pre and
post-treatment heart rate was more remarkable in the favipiravir group
than the HQ group (12 [IQR:-6—70] vs. 5 [IQR:-8—41],
p<0.001, respectively).
Conclusions: Favipiravir was significantly associated with
sinus bradycardia requiring drug withdrawal. Clinicians should more
routinely implement arrhythmia monitoring for patients receiving
favipiravir.